Recently, some biologists have argued that the ratio-dependent predator-prey model is more appropriate than the Gauss-type models for modelling predator-prey interactions where predation involves searching processes. This is strongly supported by numerous laboratory experiments and observations [1, 2, 3, 4, 10, 11, 12]. Many authors [1, 5, 7, 13, 14] have observed that the ratio-dependent preda...

The dyadic interdependence of attachment security and dependency was conceptually replicated across 80 monozygotic and 47 dizygotic older twin pairs, and 214 younger heterosexual couples. Dyad members of each relationship type were similar in security and dependency. A substantial genetic contribution to dyadic attachment was indicated by higher similarity in MZ compared with DZ twins. Security...